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jpg file shown 'distorted'...how to detect them?

2019-10-23
2019-10-24
  • luigi bettelli

    luigi bettelli - 2019-10-23

    Hello.
    I've recevied some images (.jpg files) and if I open them with the usual softwares (paint or windows photos) they look ok, but on a program I need to open it (it's not a photo program, but a software with all products' informations) I see them 'distorted' (you can find the original image and how the same file looks 'distorted' attached).
    I was looking with exiftool if I could find the attribute that tells me that the image will be shown in that way, but I have no idea of which one of them could be (maybe Compression?).
    Do you have any idea? My goal is to find all the images that will have the same problem, without opening each one of them.
    Thanks!

     
  • luigi bettelli

    luigi bettelli - 2019-10-23

    I've done one test: saved that image with Paint and now I see it ok in my program.
    I've run exiftool on both the 'not-paint' and the 'paint' version and these are the differences:

    'not-paint version' -> 'paint version'

    Blue X : 0.15 -> 0.15589
    Blue Y : 0.05999 -> 0.06604
    File Size : 3.8 MB -> 1041 kB
    Gamma : -> 2.2
    Green X : 0.3 -> 0.32121
    Green Y : 0.6 -> 0.59787
    Pixels Per Unit X : 5906 -> 4724
    Pixels Per Unit Y : 5906 -> 4724
    Red X : 0.63999 -> 0.6485
    Red Y : 0.33001 -> 0.33088
    White Point X : 0.31269 -> 0.34575
    White Point Y : 0.32899 -> 0.35855

    Should be one of them causing the problem, right?
    Thanks.

     
  • StarGeek

    StarGeek - 2019-10-23

    Just to clarify, the distortion is the fact that the image is shifted upwards? Because I don't see any actual distortion. The images otherwise look exactly the same to me.

    Your original image is not a jpg, it's a PNG file with a transparent background. If you load it into a program such as GIMP, you can see the the transparency.

    Your program appears to be auto-cropping the image. Some of the items you listed (blue, red, green, white and gamma items) will affect the colors, as they appear to be part of the ICC Profile, but the differences are very small and should be hardly visable. Nothing else in the listing will otherwise affect the display.

     
  • luigi bettelli

    luigi bettelli - 2019-10-23

    Hello.
    Thanks for replying.
    For 'distortion' I mean those loads of vertical lines that you can see in the image_distorted.jpg file (see the red arrows in the new attached).
    I've seen that it says
    File Type : PNG
    File Type Extension : png
    MIME Type : image/png
    but also after having saved the image with Paint it's saying the same, but it's shown ok, so it shouldn't be the problem.
    Thanks!

     
  • StarGeek

    StarGeek - 2019-10-23

    Ah, then the problem is with the image itself, not anything to do with the metadata. Nothing exiftool can do to fix this or flag it.

    Those lines are part of the original image, but are hidden by the embedded Alpha Channel. Your other software does not recognize the Alpha Channel. I downloaded your original and viewed it in Irfanview with the transparency setting turned off and they were clearly visible in the original.

     
  • luigi bettelli

    luigi bettelli - 2019-10-23

    Oh that's very interesting...
    So it seems I can't detect this problem without watching any single image...
    I should ask to send me those images again, but I actually don't know what to ask for not having this problem anymore..
    Just being curious, why I'm not seeing those lines after saving the image with Paint?
    Thanks!

     
  • StarGeek

    StarGeek - 2019-10-24

    I'd say that Paint is doing the equivilant of the Flatten Layers command in Photoshop.

     
  • luigi bettelli

    luigi bettelli - 2019-10-24

    Ok, thanks!
    I'll try contacting the supplier with all these info.
    Cheers.

     

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